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winmail.dat ?

13th March 2009, 01:50

I'm in the middle of working on a project to bring our mail in house onto an exchange system. We're currently in a test cutover period, and certain people are using both the pre-existing SMTP/POP solution AND exchange.
Anyone using both systems is using the Exchange server as the SMTP server, and using authentication to send email. I can see the emails in the tracking center, but that doesn't give me a lot of help.

My boss, who is one of the primary testers (it's good he's on board.. cause everyone else will follow when he mandates it )
has noted the following error:

Occasionally, you receive an email from people (within the organisation) that has a winmail.dat attachment, instead of the attachment you expect to see. You then forward it on to a list, or another person, with comments, and they don't see your comments, but do see the earlier email trail, and the proper attachment, but not the winmail.dat file.

I've found a number of Knowledge Base articles about it, and I'm reading through all of thme.. but they mostly seem to refer to non-Outlook clients.. everyone within the organisation uses outlook 2007.

Comment

but we are the receiver and the sender, and it's only happening when we send attachments.

One possible option we've done is to roll back thoe Outlook 2007 junk filter patch we applied...
but i don't think it's this.

Basically, I send an email to a collegue, with a project document attached.
He adds some comments to it, forwards it on to my boss.
My boss gets an email with the winmail.dat file, but no project document.
He adds some omre comments, namely "andy what the fxxk is causing this ?" and forwards it on to me.

I get the actual project document, but don't see his comments to me...

Comment

but we are the receiver and the sender, and it's only happening when we send attachments.

One possible option we've done is to roll back thoe Outlook 2007 junk filter patch we applied...
but i don't think it's this.

Basically, I send an email to a collegue, with a project document attached.
He adds some comments to it, forwards it on to my boss.
My boss gets an email with the winmail.dat file, but no project document.
He adds some omre comments, namely "andy what the fxxk is causing this ?" and forwards it on to me.

I get the actual project document, but don't see his comments to me...

I have had the same trouble as you recently with the winmail.dat attachment appearing for some recipients at one of the organisations we look after. I discovered it was mainly from 1 or 2 senders who were regularly sending them emails. I contacted thos senders and talked them through changing their settings in their Outlook address book for our contacts, so emails were sent as plain text.

There is also file conversion software, freely available if you google search, that will allow you to convert the winmail.dat in to attachments. e.g. An email received had two attachments but 1 winmail.dat. I installed the conversion tool, dropped the winmail.dat file over it and then 'hey presto', two word documents appeared in the location of the program, both fully entact.

Comment

I actually received one of these emails this morning. Our office administrator had copied some data from an Access Databse and pasted it into an email which she sent to me.
The email arrived as a plaintext email, with a winmail.dat file attached.

She was previously sending via our internet provider;'s SMTP gateway, so I changed and confirmed she was definitely sending via our SMTP server, and resent the email. Same thing.

So we re-opened the email, and before sending it again, went to the options tab, and ensured that HTML was selected for the format.

Same issue occured - I got a winmail.dat file.

And: my colleague has just deliberately sent me data copied and pasted from other office programmes, specifically formatted as RTF, and it has come through as we would expect without the winmail.dat file.

I have gone through ESM > Internet Message Format > Message Format and ensured that 'Exchange Rich-text format" is set to never use.

Our SMTP connector DOES use our internet provider as a smarthost.
I am considering reviewing this option and removing it to see if it assists.

Any other thoughts so far ?
I'd love to be able to convincingly say to my boss it's specificlaly related to the fact that some of us are running dual-email configurations and once we do a full cutover to exchange it won't happen.. but I'm not confident of this

Comment

I'm using the OA's email account at the moment, and I confirmed my contact detail was "let outlook choose the best format"
I changed this to RTF, and resent the troublesome email, and it was received perfectly.

Comment

I found a fix. I tracked it down to the .nk2 file on the sending machines. Potentially this file has been carried forward from prior versions of outlook, or brought over from migrated systems (xp - vista upgrades, etc). On the sending machines, you can delete .nk2 files and have them re-populate correctly, or you can have the sender just remove the entries for receivers complaining of the winmail.dat attachments. It came down to this. If the autocomplete entry in the nk2 file is “common name” "<email address> for example Ted Jones [email protected] it will send all emails to a receiving ex2k7 server as text with winmail.dat. If you delete the entry (start typing the email address, select the entry you want to delete and press delete key) and then type it in directly it will re-populate the nk2 file with what the ex2k7 server likes - an nk2 file with only the email address in the autocomplete field (no common name) - example: [email protected].
You can view the nk2 files with this utility http://www.nirsoft.net/utils/outlook...ocomplete.html
I tested on two outside sources where they started sending in winmail.dat files after our migration to exchange 2007 (problem did not exist on ex 2003 server).

Comment

I went through a migration from Exch 5.5 and Exch 2000 on separate domains to a full 2003 Clustered environment a few years back .

Part of this solution was to migrate ALL users to outlook 2003 SP2 on XP SP2.

The odd thing is after the migration completed I was still getting internal and external winmail.dat errors on mails with attachments.

The resolution turned out to be the anti virus scanner for Exchange which was running on each clustered node. It was an error which required a hotfix from the supplier. The issue was that when attachments were scanned , the AV engine was appending its own characters inside the attachment and causing Outlook to no longer understand them hence the ".dat" Attachment.

Posting this as it caused me grief for months so I hope it helps someone